CN1665953A - Process for producing aluminum material for electrolytic capacitor electrode, aluminum material for electrolytic capacitor electrode and electrolytic capacitor - Google Patents

Abstract

An aluminum ingot is subjected to hot rolling, cold rolling and then intermediate annealing to obtain a rolled article. Tensile strain is applied to the rolled article without subjecting the rolled article to cold rolling after the intermediate annealing but before initiation of final annealing, and thereafter the rolled article is subjected final annealing. An application of the tensile strain is performed using a tensile strain application equipment 1 having two or more bridle roll units 10 and 11 disposed in a transferring direction of the aluminum material S for forming a tension applying area Q between adjacent bridle roll units 10 and 11 in such a manner that between a peripheral speed Pi of an upstream-side bridle roll unit and a peripheral speed Po of a downstream-side bridle roll a peripheral speed difference of Pi<Po is provided so as to continuously generate plastic elongation in the tension applying area Q.

Description

Manufacturing method of aluminum material for electrolytic capacitor electrode, aluminum material for electrolytic capacitor electrode, and electrolytic capacitor

This application is the Japanese patent application No. 2002-188860 filed on June 28, 2002, the Japanese patent application No. 2002-338765 filed on November 22, 2002, and the Japanese patent application filed on December 12, 2002 No. 2002-361131, Japanese Patent Application No. 2003-144058 filed on May 21, 2003, and U.S. Patent Application No. 60/462,333 filed on April 14, 2003, the disclosure content of which directly constitutes this part of the application.

                      

This application is a response to U.S. Provisional Application No. 60/462,333, filed April 14, 2003, under § 111(b) of the U.S. Patent Act, claiming a filing date under § 119(e)(1) of the U.S. Patent Act interest, filed under Section 111(a) of the United States Patent Act.

technical field

The present invention relates to a method for manufacturing an aluminum material for an electrode of an electrolytic capacitor, an aluminum material manufactured by the method, and an electrolytic capacitor using the aluminum material.

In addition, in this specification, "aluminum" is used in the meaning which includes both aluminum and its alloy, and an aluminum material includes at least an aluminum foil, an aluminum plate, and these molded objects.

Background technique

Conventionally, aluminum materials for electrolytic capacitor electrodes have been produced by performing various treatments on an ingot with an aluminum purity of 99.8% or more in the order of hot rolling, first cold rolling, intermediate annealing, second cold rolling, and final annealing. , such as anode materials for electrolytic capacitors for medium and high voltages. Then, electrolytic etching was performed on the anode material of the electrolytic capacitor for medium and high voltage to form tunnel-like pits, and then a chemical conversion treatment was performed to obtain an anode material. Therefore, in order to obtain an anode material having a high electrostatic capacity, the etching characteristics of the aluminum material must be good, and various attempts have been made to improve the etching characteristics.

It is well known that the relationship between the electrolytic etching characteristics and grain structure in aluminum materials, for example, in the anode material for medium and high voltage that forms tunnel-like pits by electrolytic etching, the more cube oriented grains (cube oriented grains), that is, the cubic The higher the orientation occupancy rate, the more effectively the surface area of the aluminum material can be expanded to obtain a high electrostatic capacity. Furthermore, as a method of obtaining an aluminum material having a high cubic orientation ratio, for example, the following methods are proposed.

In Patent Document 1 (Japanese Patent Publication No. 54-11242), it is disclosed that after the first cold rolling with a high cold hardening rate of 1000% or more, intermediate annealing is performed at 180 to 350° C., and then A method of obtaining an aluminum material with a high cubic orientation ratio by performing the second cold rolling at a rolling reduction of 5% to 35%, and then performing final annealing.

In addition, in Patent Document 2 (JP-A-6-145923), it is disclosed that intermediate annealing is performed after the first cold rolling at a high pressure reduction ratio of 90% or more, and then a reduction ratio of 10 to 40% is implemented. In the second cold rolling, the tensile strain is adjusted to 0.2 to 5.0% in the process from the start of the second cold rolling to the start of the final annealing, thereby obtaining an aluminum material with a high cubic orientation ratio method.

In these methods, after the intermediate annealing, the second cold rolling is performed at a low rolling reduction to control the crystal orientation and increase the occupancy of the cubic orientation.

On the other hand, the demand for higher performance of capacitors, that is, higher capacitance of electrode materials has been rapidly increasing in recent years. Here, as one of the methods for obtaining a high electrostatic capacity, there is a method of further enlarging the surface area by increasing the length (depth) of the etching pit. At this time, since the non-etched portion located in the core of the anode material cannot be thinned to ensure the bending strength of the etched material, the thickness of the anode material must be increased in order to increase the surface area by increasing the length of the etching pit.

Conventionally, aluminum materials for electrolytic capacitor anodes generally have a thickness of about 100 μm. Therefore, in order to increase the electrostatic capacity by increasing the thickness, it is necessary to develop a material with a thickness exceeding 100 μm.

Furthermore, since the method described in the above-mentioned patent document requires the second cold rolling after the intermediate annealing, it is necessary to perform degreasing and washing to remove the lubricant used in the second cold rolling before the final annealing. In addition, since the rolling reduction in the second cold rolling is low and the amount of lubricant brought into the coil after rolling is large, the detergent is easily deteriorated and the washing tank is also easily contaminated. As described above, in the conventional manufacturing method, since the number of working steps increases and a large amount of detergent is consumed, simplification of the process is required.

In addition, in the conventional general production method including the above-mentioned prior art example, that is, in the method of performing intermediate annealing after cold rolling, and performing cold rolling at a small reduction ratio after the intermediate annealing until before the start of final annealing, if When the thickness of the aluminum material is 110 μm or above, grain coarsening is likely to occur during the final annealing. As the thickness increases further, grain coarsening is more likely to occur significantly, and the control of the grain structure is very difficult. This is considered to be because the strain distribution in the material by cold rolling performed after the intermediate annealing has a large influence.

In addition, such coarsening of crystal grains almost always occurs in crystal grains having an orientation other than the cubic orientation. In this case, a portion with a low electrostatic capacity remarkably occurs in the aluminum material, which becomes a very serious problem.

Therefore, there is a need for a method capable of stably producing an aluminum material for an electrolytic capacitor electrode having a high cubic crystal occupancy rate and controlling the thickness of grain coarsening to 110 μm or more.

Contents of the invention

In view of the above circumstances, the object of the present invention is to provide a method for producing an aluminum material for an electrolytic capacitor electrode capable of producing an aluminum material having a high cubic orientation ratio in a simpler process than conventional ones, and an aluminum material and a material for an electrolytic capacitor produced by the method. Aluminum electrolytic capacitors.

It is also an object of the present invention to provide a method for manufacturing an aluminum material for an electrolytic capacitor electrode with a high cubic orientation occupancy rate and a thickness that controls crystal grain coarsening by a method different from the above-mentioned prior art, and the method thereof Manufactured aluminum and electrolytic capacitors made of aluminum.

In order to achieve the above-mentioned object, the manufacturing method of the aluminum material for electrolytic capacitor electrodes of this invention has the structure as described in following (1)-(17).

(1) A method of manufacturing an aluminum material for an electrode of an electrolytic capacitor, wherein an aluminum ingot is hot-rolled and cold-rolled, and then intermediate annealing is performed, and cold rolling is not performed between the intermediate annealing and the start of final annealing On the other hand, tensile strain is imparted, and final annealing is performed thereafter.

(2) The method for producing an aluminum material for an electrolytic capacitor electrode as described in the above item (1), wherein a tensile strain of 1 to 15% is applied.

(3) The method for producing an aluminum material for an electrolytic capacitor electrode as described in the above item (2), wherein a tensile strain of 3 to 12% is applied.

(4) The method for manufacturing an aluminum material for an electrolytic capacitor electrode as described in any one of the preceding items (1) to (3), characterized in that by using The tension roll unit, the tensile strain imparting device that forms a tension zone between the adjacent tension roll units, and the peripheral speed Pi in the upstream side tension roll unit and the peripheral speed Po in the downstream side tension roll unit set Pi The difference in peripheral speed < Po allows continuous plastic stretching in the above-mentioned tension region to impart tensile strain.

(5) The manufacturing method of the aluminum material for electrolytic capacitor electrodes as described in said item (4), wherein said peripheral speed Pi, Po satisfy the relationship of 0<(Po-Pi)/Pi≤0.1.

(6) The method for manufacturing an aluminum material for an electrolytic capacitor electrode described in the preceding item (4) or (5), wherein the tensioning of the upstream side tension roller unit and the downstream side tension roller unit are operated at different numbers of revolutions. The rollers generate the aforementioned difference in peripheral speed.

(7) The manufacturing method of the aluminum material for electrolytic capacitor electrodes described in any one of the preceding items (4) to (6), wherein, by making the diameter of the tension roll of the downstream side tension roll unit be larger than that of the upstream side tension roll The diameter of the tension roller of the unit is larger, which produces the above-mentioned peripheral speed difference.

(8) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of the preceding items (1) to (7), wherein, in one rolling pass for imparting tensile strain, two or two Tensile strain is imparted above.

(9) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of the above items (1) to (8), wherein rolling passes for imparting tensile strain are performed a plurality of times.

(10) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of (4) to (9) above, wherein the tensile strain imparting device is a roller tension leveler device.

(11) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of (1) to (10) above, wherein the intermediate annealing and the provision of tensile strain are performed continuously.

(12) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of (1) to (11) above, wherein the provision of tensile strain and the final annealing are performed continuously.

(13) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of the above items (1) to (12), wherein an aluminum material having a thickness of 110 to 230 μm is produced.

(14) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of the preceding items (1) to (13), wherein the 0.2% yield strength in the rolling direction of the aluminum material after intermediate annealing is 25 to 100 MPa .

(15) The method for producing an aluminum material for an electrolytic capacitor electrode according to any one of the preceding items (1) to (14), wherein, in terms of a diameter corresponding to a circle, the surface of the aluminum material after final annealing does not have more than Coarse grains with a size of 2 mm.

(16) The method for producing an aluminum material for electrolytic capacitor electrodes according to any one of the above items (1) to (15), wherein the aluminum material is an anode material.

(17) The method for producing an aluminum material for electrolytic capacitor electrodes according to any one of (1) to (16) above, wherein the aluminum material is an anode material for medium and high voltages.

The aluminum material for electrolytic capacitor electrodes of this invention has the structure described in following (18).

(18) An aluminum material for electrolytic capacitor electrodes, which is produced by the method described in any one of the preceding items (1) to (17).

The electrolytic capacitor of the present invention has the configuration described in (19) below.

(19) An electrolytic capacitor characterized in that the aluminum material for electrolytic capacitor electrodes described in the preceding item (18) is used as an electrode material.

According to the manufacturing method of the aluminum material for electrolytic capacitor electrodes of the present invention, it is possible to stably obtain an aluminum material for electrolytic capacitor electrodes that has a high cubic orientation ratio and can also control grain coarsening. Therefore, by etching such an aluminum material, the area expansion rate can be increased and the electrostatic capacity can be increased.

Furthermore, since no lubricant is used in the tensile strain imparting step, final annealing can be performed without degreasing and washing. Therefore, it is possible to manufacture an aluminum material having a high cubic orientation ratio in a simplified process without degreasing and washing which is indispensable in a conventional manufacturing method of cold rolling using a lubricant after intermediate annealing. In addition, since there is no degreasing washing process, the cleaning agent used in the degreasing washing and the management of the washing tank can be eliminated.

In addition, when the tensile strain to be applied is 1 to 15%, a particularly high cubic orientation occupancy can be obtained.

In addition, when the tensile strain to be applied is 3 to 12%, a higher cubic orientation occupancy can be obtained.

Tensile strain can be effectively imparted as a method for imparting tensile strain by using a tension roll unit having two or more units arranged in the conveying direction of the aluminum material, and an Tensile strain imparting device that forms a tension zone between the units. For the peripheral speed Pi of the upstream side tension roller unit and the peripheral speed Po of the downstream side tension roller unit, a difference in peripheral speed of Pi<Po is set. Within the above tension region Plastic stretching occurs continuously.

In addition, by setting the peripheral speeds Pi and Po so as to satisfy the relationship of 0<(Po-Pi)/Pi≦0.1, defects and fractures of the aluminum material can be avoided, and predetermined tensile strain can be reliably imparted.

The above peripheral speed difference can be generated by operating the tension rollers of the upstream side tension roller unit and the downstream side tension roller unit at different numbers of revolutions.

In addition, the above peripheral speed difference can be generated by making the diameter of the tension rollers of the downstream side tension roller group larger than that of the upstream side tension roller group.

Tensile strain can be applied multiple times by applying tensile strain at two or more points in one rolling pass for applying tensile strain.

In addition, the tensile strain may be applied multiple times by performing the rolling pass for applying the tensile strain a plurality of times.

In addition, a roller tension leveler device can be used as the above-mentioned tensile strain imparting device, and a desired tensile strain can be imparted while correcting shape defects such as flatness.

An aluminum material can be efficiently produced by performing intermediate annealing and tensile strain imparting continuously.

An aluminum material can be efficiently produced by continuously performing tensile strain imparting and final annealing.

In the case of producing an aluminum material having a thickness of 110 to 230 μm in a thickness range in which grain coarsening tends to occur, the significance of the present invention for controlling grain coarsening becomes even greater.

In addition, when the 0.2% yield strength in the rolling direction after the intermediate annealing is 25 to 100 MPa, a higher cubic orientation occupancy can be obtained.

In addition, since there are no coarse crystal grains larger than 2 mm on the surface of the aluminum material after final annealing in terms of a diameter equivalent to a circle, it is possible to prevent a decrease in capacitance due to such coarse grains and to realize high capacitance stably. electrostatic capacity.

In addition, by using the aluminum material produced by the present invention as an anode material and an anode material for medium and high voltages, an anode material with a large electrostatic capacity can be constituted.

In addition, an electrolytic capacitor using the aluminum material produced by the present invention as an electrode material has a large electrostatic capacity.

A brief description of the drawings

FIG. 1 is a schematic view showing an example of a tensile strain imparting device used in the method for producing an aluminum material for an electrolytic capacitor electrode of the present invention.

Fig. 2 is a schematic diagram showing another example of the tensile strain imparting device.

Fig. 3 is a schematic view showing an example of a manufacturing process of an aluminum material for an electrolytic capacitor electrode.

Fig. 4 is a schematic view showing another example of the manufacturing process of the aluminum material for electrolytic capacitor electrodes.

Detailed ways

In the method for producing an aluminum material for an electrolytic capacitor electrode of the present invention, in order to impart as uniformly distributed strain as possible in the thickness direction of the material after the intermediate annealing, tensile strain is applied without cold rolling after the intermediate annealing, followed by performing Final annealing. Through such a process, an aluminum material for an electrolytic capacitor electrode, particularly an aluminum material having a thickness of 110 to 230 μm, can be obtained while ensuring a high cubic orientation ratio and suppressing coarsening of crystal grains.

Although the cubic orientation occupancy can be increased by slightly applying the aforementioned tensile strain, it is preferably 1% or more in order to obtain a high cubic orientation occupancy. On the other hand, 15% or less is preferable because the aluminum material may be broken during stretching if the tensile strain is excessively applied. A particularly preferred tensile strain is 3 to 12%, more preferably more than 5% but 10% or less. Furthermore, the final annealing of the aluminum material to which tensile strain is applied allows the crystal grains having a cubic orientation to grow, and a final high occupancy of the cubic orientation can be obtained.

The method of imparting tensile strain is not particularly limited. For example, by rolling the aluminum material into an uncoiled coil, braking the uncoiled coil, and winding the coiled coil at the same time, it is possible to apply tensile force to the aluminum material in the middle of moving from the uncoiled coil to the coiled coil. And the method of imparting tensile strain.

In addition, the tensile strain may be imparted by uniaxial stretching in one direction, for example, only in the longitudinal direction with respect to the aluminum material, or by uniaxial stretching in two different directions, for example, in the longitudinal direction. Biaxial stretching that imparts stretching force in both direction and width direction. In addition, bending and deforming aluminum can also produce tensile strain.

As a particularly effective tensile strain imparting method, the use of a tensile strain imparting device having two or more tension roll units arranged in the conveying direction of the aluminum material and forming a tension zone between adjacent tension roll units is recommended.

FIG. 1 schematically shows an example of a tensile strain imparting device, and a tensile strain imparting method using the device will be described in detail.

The tensile strain imparting device (1) has two sets of upstream side tension rollers (10) arranged on the upstream side along the conveying direction of the aluminum material (S) and downstream side tension rollers (11) arranged on the downstream side. A tension roller unit forms a tension zone (Q) between its units (10) (11). Set such that the peripheral speed Pi in the upstream side tension roller unit (10) and the peripheral speed Po in the downstream side tension roller unit (11) become Pi<Po, the peripheral speed difference is within the tension region (Q) The aluminum material (S) is continuously plastically stretched to impart tensile strain. In addition, the above-mentioned upstream side and downstream side tension roller units (10) (11) are respectively composed of 4 tension rollers (12) (12) (12) (12), (13) (13) (13) (13) configuration, but the number of rollers and arrangement of rollers are not limited to this embodiment, and can be set arbitrarily.

In addition, the aforementioned peripheral speeds Pi and Po preferably satisfy the relationship of 0<(Po-Pi)/Pi≤0.1, and more preferably satisfy the relationship of 0.01≤(Po-Pi)/Pi≤0.1. Tensile strain can be imparted as long as a peripheral velocity difference within the range of Pi<Po, that is, 0<(Po-Pi)/Pi occurs, but further by satisfying 0.01≤(Po-Pi)/Pi, it can be particularly effective Assign tensile strain. On the other hand, when (Po-Pi)/Pi>0.1, the possibility that defects are generated on the surface of the aluminum material due to slip or that the aluminum material is broken increases. Therefore, by satisfying the relationship of (Po-Pi)/Pi≦0.1, defects and fractures of the aluminum material can be avoided, and a predetermined tensile strain can be reliably imparted.

In addition, as a method for producing the above-mentioned peripheral speed difference, it is possible to operate the tension roller (12) of the upstream side tension roller unit (10) and the tension roller (12) of the downstream side tension roller unit (11) at different revolutions 13), or a method of making the diameter of the tension roller (13) of the downstream tension roller unit (11) larger than the diameter of the tension roller (12) of the upstream tension roller unit (10). Alternatively, both the number of revolutions of the roller and the diameter of the roller may be different, or a difference in peripheral speed may be generated.

In addition, the number of times of tensile strain application does not have to be one time, and may be applied multiple times. In particular, when a large tensile strain is applied, it is preferable to apply the tensile strain multiple times. The reason for this is that depending on the surface condition of the conveyed material, the possibility of slipping on the contact surface between the tension roller and the material surface increases to cause defects, and the material tends to wrinkle in the tension application area. A method to perform assignment multiple times. In addition, wrinkling can be suppressed by using a pinch roller or the like that constrains the material in the tension region.

When performing tensile strain imparting multiple times using the tensile strain imparting device ( 1 ) having the above-mentioned one tension region (Q), it is only necessary to implement a plurality of rolling passes. In addition, tensile strain may be applied multiple times in one rolling pass. For example, the tensile strain imparting device (2) shown in Fig. 2 has 3 tension roller units (20) (21) (22), with 2 groups of adjacent tension roller units (20) (21), ( 21)(22) can form 2 tension areas (Q1)(Q2).

Furthermore, by installing the above-mentioned tensile strain imparting device (2) on the conveying path of the aluminum material (S), it is possible to perform tensile strain imparting twice in one rolling pass. In this way, as long as two or more stretching roll units are added to apply tensile strain, multiple times of tensile strain can be applied in one rolling pass. In addition, rolling passes in which tensile strain is applied may be performed multiple times at a plurality of places per one rolling pass. In addition, in addition to using one tension roll unit (21) in the formation of the two tension regions (Q1) (Q2) as the above-mentioned tensile strain imparting device (2), continuously setting the tension regions (Q1) (Q2) ), it is also possible to set up two tension zones separately without using the tension roller unit.

In addition, the said tensile strain imparting apparatus (1) (2) can also use the apparatus conventionally used as a roller tension leveler apparatus. That is, use a straightening device that gives plastic deformation to a part of the cross section of the strip by tension below the yield point and stress increase caused by bending, gives the strip a residual stretch, and straightens defects such as flatness, by such as By adjusting the peripheral speed conditions of the tension roll as described above, a desired tensile strain can be imparted. Accordingly, a desired tensile strain can be imparted while straightening the flatness in the roller tension leveler device.

In addition, there is no particular limitation on the delivery method after supplying the aluminum material to the above-mentioned tensile strain imparting step and imparting tensile strain. In the process illustrated in Figures 3 and 4, a looper pick (31) is provided behind the uncoiler (30) to convey the aluminum material (S) at a specified speed, and at the same time, coils are spliced at (R1), and multiple coils The tensile strain imparting device (32) is continuously supplied. In addition, a loop pick (34) is provided in front of the coiler (33), and the aluminum material (S) after the tensile strain is provided is conveyed at a predetermined speed, and the aluminum material (S) is cut at (R2) at the same time, and the coil is divided. and move out. In addition, in Fig. 3, 4, (35) is the standby roll for loading on the uncoiler (30) next, (36) is the roll that is coiled and divided, and (37) is an annealing furnace described later. Through such continuous processing, time losses caused by arranging coil exchanges in the uncoiler (30) and coiler (33) can be avoided.

The tensile strain imparting step does not necessarily have to be one step, nor does it necessarily have to be applied at one time. Therefore, even if the step of applying tensile strain involves multiple steps or involves multiple times, there is no problem, as long as the intermediate annealing is usually performed at 200 to 300°C, and the process is carried out at 450°C or higher. It is sufficient to apply tensile strain before the final annealing begins. In addition, steps such as washing and dividing may be added before and after the step of imparting tensile strain. In addition, at least one or at least one or more of the intermediate annealing step, washing step, splitting step, and final annealing step and the step of imparting tensile strain may be performed continuously in one device, or may be performed simultaneously. .

Intermediate annealing is generally performed at 200 to 300° C., and the higher the temperature, the shorter the treatment time. However, the characteristics of the aluminum material after intermediate annealing are important. During intermediate annealing, if the recrystallization of the aluminum material is excessively advanced by high temperature or long-term treatment, that is, if it is too softened, it will be difficult for the crystal grains with cubic orientation to grow preferentially during final annealing, and the cubic orientation occupancy rate will decrease. . On the other hand, in the intermediate annealing, if the recrystallization is suppressed too much, that is, the softening is suppressed too much by the low-temperature or short-time treatment, the cube-orientation nuclei decrease, and the cubic-orientation occupancy after final annealing decreases. Therefore, the 0.2% yield strength in the rolling direction of the aluminum material after the intermediate annealing is preferably 25 to 100 MPa, particularly preferably 35 to 90 MPa.

The method of intermediate annealing is not particularly limited, for example, the method of batch annealing the aluminum material made into a coil, and when uncoiling from a decoil and coiling into a coil, between decoil and coil A method of continuously annealing the conveyed aluminum material between coils.

In addition, intermediate annealing and tensile strain imparting may be performed continuously. For example, as shown in FIG. 3 , the aluminum material (S) sequentially conveyed by the uncoiler (30) is supplied to an annealing furnace (37) for intermediate annealing, and then supplied to a tensile strain imparting device (32) for imparting tensile strain.

In addition, tensile strain imparting and final annealing may be performed continuously. For example, as shown in FIG. 4, if the annealing furnace (37) is arranged at the rear stage of the tensile strain imparting device (32), the aluminum materials (S) sequentially conveyed by the uncoiler (30) can be supplied to the tensile strain imparting device. (32) Tensile strain is imparted, then supplied to an annealing furnace (37), and final annealing is performed.

In addition, an annealing furnace may be arranged before and after the tensile strain imparting device, and intermediate annealing, tensile strain imparting, and final annealing may be performed continuously.

In this manner, an aluminum material can be efficiently produced by performing intermediate annealing, tensile strain imparting, and final annealing continuously.

In addition, a compressive deformation of 5% or less is allowed to be imparted at the same time as the tensile strain is imparted or before or after the tensile strain is imparted. This compressive deformation can be performed while pinching the aluminum material conveyed from the unwinding coil to the coiling coil by a pair of pinch rolls, for example. In addition, this compression deformation can be imparted without using a lubricant.

It is not necessary to use any lubricant in the above-mentioned process of imparting tensile strain and compression process. Therefore, degreasing and washing before the final annealing, which is indispensable in the conventional manufacturing method of performing the second cold rolling after the intermediate annealing using a lubricant, can be simplified, and the manufacturing process can be simplified. In addition, no detergent is required, and at the same time, the management work of the washing tank accompanying degreasing washing can be eliminated.

In addition, there are deposits such as contamination on the surface of the aluminum material. In order to obtain excellent etching characteristics, these deposits must be cleaned before final annealing. Even in this case, since there is almost no lubricant brought in by the aluminum material, the washing process can be shortened and the washing process can be shortened, and contamination and deterioration of the washing liquid can be prevented. In addition, since the above-mentioned process of imparting tensile strain may be performed independently or simultaneously with other processes, the process of removing such deposits on the surface of the aluminum material and imparting of tensile strain may be performed simultaneously.

In the present invention, the manufacturing conditions other than the tensile strain imparting step are not limited in any way, and each step of hot rolling, cold rolling, and finish annealing can be performed according to known conditions. In addition, in the process before the intermediate annealing, the removal and washing of impurities and oil on the surface of the aluminum material can be performed suitably. In addition, in the intermediate annealing, as mentioned above, since the 0.2% yield strength of the aluminum material after the intermediate annealing is preferably 25-100 MPa, particularly preferably 35-90 MPa, it is only necessary to adjust the conditions appropriately to obtain such conditions.

In addition, before hot-rolling the aluminum ingot, it is also possible to perform a flat cutting process for removing the surface of the ingot. In addition, homogenization treatment may be performed before hot rolling according to a conventional method.

In addition, in the above-mentioned series of manufacturing processes, the method of using the tensile strain imparting device by the tension roll unit was described as an example as the tensile strain imparting method, but the number of times of the tensile strain imparted, the rolling pass The description of the number of times, the continuous treatment with intermediate annealing, the continuous treatment with final annealing, the supply method of the aluminum material to the tensile strain imparting step, and the unloading method after tensile strain imparting is not limited to the use of the above tensile strain In the case of the imparting device, it is also applicable to the case of using another tensile strain imparting device.

The composition of the aluminum ingot is not limited, and an aluminum ingot used as an electrode material of an electrolytic capacitor can be suitably used. Specifically, in order to limit the amount of impurities and prevent deterioration of etching properties due to overdissolution, the aluminum purity is preferably 99.8% by mass or higher, particularly preferably 99.9% by mass or higher. In addition, in order to improve etching characteristics and strength, aluminum materials to which various trace elements are added are also suitably used.

In addition, the thickness of the aluminum material produced by the method of the present invention is not limited. An aluminum material of 200 μm or less called foil, and an aluminum material thicker than that are included in the present invention. In the present invention, the thickness of the aluminum material after the final annealing is recommended to be 110 to 230 μm. The reason is that when the thickness is 110 μm or more, the crystal grains tend to be coarsened during the final annealing, and the significance of using the present invention is even greater. big. Conversely, at a thickness of 110 μm or less, even if the present invention is not used, the coarsening of crystal grains does not become too much of a problem. On the other hand, when the thickness of the aluminum material exceeds 230 μm, even if the present invention is used, it is difficult to suppress the coarsening of the crystal grains, and when the crystal grains are observed from the surface of the aluminum material, the diameter corresponding to a circle may, for example, exceed 2 mm. of grains. The lower limit of the thickness of the aluminum material after final annealing is preferably 115 μm, more preferably 120 μm. On the other hand, the upper limit of the thickness is preferably 210 μm, more preferably 200 μm.

The aluminum material produced according to the present invention can be subjected to etching for increasing the subsequent area expansion ratio. Since the aluminum material has a high cubic orientation ratio due to the provision of tensile strain and the subsequent final annealing, a good area ratio of expansion can be obtained by etching. The aluminum material produced by the present invention can be used as both a cathode material and an anode material, especially through the chemical conversion treatment after etching, even if a voltage-resistant film is formed, it has a large effective area, and it is suitable for the anode material from this point . In addition, even among anode materials, it is also suitable as an electrode material for electrolytic capacitors for medium voltage and high voltage. In addition, an electrolytic capacitor using this electrode material can realize a large capacity.

Example

[manufacturing example 1]

The aluminum ingots of types A and B shown in Table 1 were used to manufacture aluminum materials.

First, the homogenization treatment was performed under the conditions of ingot A: 610° C.×10 hours, and ingot B: 610° C.×20 hours.

Next, after performing hot rolling and cold rolling, intermediate annealing was performed under each condition shown in Table 2, and the test material of 100 mm x 300 mm was cut out after intermediate annealing. Furthermore, in Examples 1 to 8, a tensile strain was imparted in the longitudinal direction of the test material with a uniaxial tensile testing machine. In addition, in Example 8, the test material was passed between pinch rolls without using a lubricant and pressed. Lower rate of 1.1% compression set. On the other hand, Comparative Examples 1 and 2 did not provide tensile strain. Then, each test material was subjected to final annealing under each condition shown in Table 2.

The thickness of the obtained aluminum material after final annealing was measured, and the cubic orientation occupancy on the surface was investigated at the same time. The results are shown in Table 2.

Table 1 Ingot No. Chemical composition (unit: Al is mass%, other elements are mass ppm) Si Fe Cu mn Mg Zn Ti B Pb Al A twenty three 16 49 1 1 10 1 1 0.6 99.98 or more B 46 60 18 2 5 12 1 4 0.7 99.98 or more

Table 2 Example comparative example 1 2 3 4 5 6 7 8 1 2 Ingot Composition A A A A A A B B A A intermediate annealing 250℃×20 hours 250℃×10 hours 300℃×6 hours 250℃×20 hours 250℃×10 hours Tensile strain (%) 0.5 2.3 6.1 10.0 5.2 5.2 5.2 6.2 - - Compression deformation reduction ratio (%) - - - - - - - 1.1 - - final annealing 540℃×4 hours 550℃×2 hours 540℃×4 hours Thickness (μm) 145 144 143 149 114 73 122 119 145 72 Cube orientation occupancy (%) 78.4 92.6 99.1 99.9 98.7 86.8 95.6 88.7 49.4 55.4

As shown in the results in Table 2, high cubic orientation occupancy can be obtained by applying tensile strain after the intermediate annealing and without performing the second cold rolling. The cubic orientation occupancy is equivalent to the cubic orientation occupancy of an aluminum material produced by performing the second cold rolling after the conventional intermediate annealing. In addition, since no lubricant is used in the tensile strain imparting step, it is unnecessary to perform degreasing and washing which is indispensable in the conventional manufacturing method, and an aluminum material with excellent performance can be manufactured with a simplified process.

[Manufacturing example 2]

First, the aluminum ingot of the composition C shown in Table 3 was subjected to a homogenization treatment under the conditions of 610° C.×10 hours.

Next, after performing hot rolling and cold rolling, intermediate annealing is performed. The conditions of the intermediate annealing were appropriately adjusted so that the 0.2% yield strength in the rolling direction of the aluminum material after the intermediate annealing became the value shown in Table 4. In addition, in the tensile test for confirming the mechanical properties after the intermediate annealing, a test piece having a width of 10 mm and a length of 200 mm cut out from the aluminum material after the intermediate annealing was supplied.

Then, a test material of 100 mm×300 mm was cut out from the intermediate-annealed aluminum material so that the longitudinal direction of the test material was parallel to the rolling direction. Further, in Examples 11 to 24 and Comparative Example 14, tensile strain was applied in the longitudinal direction of the test material by a uniaxial tensile testing machine. On the other hand, Comparative Example 11 did not impart tensile strain. In addition, in Comparative Examples 12 and 13, no tensile strain was imparted after the intermediate annealing, and cold rolling was performed at the reduction ratio shown in Table 4.

Then, each test material was subjected to final annealing at 500° C. for 10 hours to obtain aluminum materials with thicknesses shown in Table 4.

The obtained aluminum material after final annealing was immersed in a solution having a volume ratio of hydrochloric acid: nitric acid: hydrofluoric acid = 50:47:3, crystal grains appeared, and the surface cubic orientation occupancy and presence or absence were investigated with an image analysis device. Coarse grains. In addition, when observing the surface of an aluminum material, whether or not there are coarse crystal grains is judged by whether or not there are crystal grains with a diameter larger than a circle equivalent to 2 mm relative to the grain area. The results are shown in Table 4.

table 3 Ingot No. Chemical composition (unit: Al is mass%, other elements are mass ppm) Si Fe Cu Zn Ga Pb Al C twenty three 15 51 11 8 0.61 99.98 or more

Table 4 Example comparative example 11 12 13 14 15 16 17 18 19 20 twenty one twenty two twenty three twenty four 11 12 13 14 Ingot Composition C C C C C C C C C C C C C C C C C C 0.2% yield strength after intermediate annealing (Mpa) 70 40 43 86 84 39 39 39 59 89 26 95 twenty four 104 39 39 40 72 Stretch should 5.2 6.0 6.5 5.2 8.0 0.5 1.0 3.3 10 5.2 6.0 5.2 6.5 5.1 - - - 6.0 Change(%) Cold rolling reduction (%) - - - - - - - - - - - - - - - 19 25 - Thickness (μm) 112 145 175 208 223 145 145 141 149 150 145 150 152 151 146 149 220 240 Cube orientation occupancy (%) 99.2 99.1 99.2 99.8 99.1 86.7 93.2 98.0 99.9 99.1 95.9 97.3 92.6 93.7 76.7 97.2 80.8 65.3 Whether there are coarse grains none none none none none none none none none none none none none none none have have have

As shown in the results of Table 4, in Examples 11 to 24, by imparting tensile strain after intermediate annealing, high cubic orientation occupancy can be obtained without performing cold rolling after intermediate annealing, and no coarse crystal grains can be recognized. occur.

In contrast, in Comparative Example 11 in which neither tensile strain nor cold rolling was performed after intermediate annealing, the cubic orientation occupancy rate was low. In addition, in Comparative Examples 12 and 13 of the conventional method in which cold rolling was performed without imparting tensile strain after intermediate annealing, the occurrence of coarse crystal grains was recognized. In addition, in Comparative Example 14 having a thickness exceeding 230 μm, coarse crystal grains were generated even when tensile strain was applied after the intermediate annealing.

[Manufacturing example 3]

In this production example, tensile strain was applied to the intermediate annealed coil using the tensile strain imparting device ( 1 ) shown in FIG. 1 .

The tensile strain imparting device (1) is a roller tension leveler device having two tension roller units (10) (11) arranged on the upstream side and the downstream side of the conveying direction of the aluminum material (S), and each unit (10) (11) are respectively made of 4 tension rollers (12) (13).

When producing an aluminum material, first, a homogenization treatment was performed at 610° C. for 10 hours on each aluminum ingot having the compositions D, E, and F shown in Table 5.

Next, after performing hot rolling and cold rolling, intermediate annealing was performed, and it produced the coil material of width 1030mm. The conditions of the intermediate annealing were appropriately adjusted so that the 0.2% yield strength in the rolling direction of the aluminum material after the intermediate annealing became the value shown in Table 6. In addition, in the tensile test for confirming the mechanical properties after the intermediate annealing, a test piece having a width of 10 mm and a length of 200 mm cut out from the aluminum material after the intermediate annealing was provided.

Using the above-mentioned tensile strain imparting device (1) for the coil after intermediate annealing, by setting the difference between the peripheral speed Pi of the upstream side tension roller unit (10) and the peripheral speed Po of the downstream side tension roller unit (11), And (Po-Pi)/Pi was set to the value shown in Table 6, and tensile strain was given to the aluminum material (S). Embodiment 31～34 is set (Po-Pi)/Pi by changing the revolution speed of tension roller (12) (13), and embodiment 35,36 is by changing the roller diameter of tension roller (12) (13) Setting, Example 37 was set by changing both the rotation speed and the roll diameter. In addition, the conveying speed of the aluminum material (S) and the number of rolling passes for applying tensile strain were set as shown in Table 6, and the tensile strain (%) shown in Table 6 was finally applied.

The aluminum material provided with tensile strain was coiled into a coil, cut into coils with a width of 500 mm, and subjected to final annealing at 500° C. for 10 hours in an argon atmosphere to obtain aluminum materials with thicknesses shown in Table 6.

A test material with a length of 200 mm and a width of 500 mm is taken from the aluminum material after final annealing in a coil, and the test material is immersed in a solution having a volume ratio of hydrochloric acid: nitric acid: hydrofluoric acid=50:47:3, Crystal grains appear, and the surface cubic orientation occupancy and the presence or absence of coarse grains are investigated with an image analysis device. In addition, when observing the surface of an aluminum material, whether or not there are coarse crystal grains is judged by whether or not there are crystal grains with a diameter larger than a circle equivalent to 2 mm relative to the grain area. The results are shown in Table 6.

table 5 Ingot No. Chemical composition (unit: Al is mass%, other elements are mass ppm) Si Fe Cu Zn Ga Pb Al D. twenty three 15 51 11 8 0.6 99.98 or more E. 20 13 58 10 9 0.6 99.98 or more f 10 9 36 9 1 1.0 99.99 or more

Table 6 Example 31 32 33 34 35 36 37 Ingot Composition D. D. D. D. E. E. f 0.2% yield strength after intermediate annealing (MPa) 39 39 39 41 62 31 57 (Po-Pi)/Pi 0.009 0.009 0.009 0.009 0.045 0.087 0.041 Number of rolling passes 2 4 6 6 2 1 2 Conveying speed(m/min) 80 80 80 80 90 80 90 Tensile strain (%) 1.4 3.3 4.1 4.3 7.6 7.8 7.0 Thickness (μm) 144 141 140 111 113 113 121 Cube orientation occupancy (%) 97.6 97.9 99.0 98.0 99.7 99.4 99.4 Whether there are coarse grains none none none none none none none

As shown in the results of Table 6, even if tensile strain is applied after the intermediate annealing and cold rolling is not performed after the intermediate annealing, a high cubic orientation occupancy can be obtained, and coarse grains do not occur. In addition, tensile strain can be effectively applied even to coils by using a tensile strain imparting device using a tension roll unit.

It should be considered that the terms and expressions used here are used for illustration, not for limiting interpretation, and do not exclude any equivalents with the characteristic items shown and described here, and also allow the invention within the claimed scope of the present invention. Various deformations.

According to the method of the present invention, it is possible to stably obtain an aluminum material for an electrolytic capacitor electrode having a high cubic orientation ratio and suppressing the coarsening of crystal grains. Therefore, by etching the aluminum material, the area expansion rate can be increased and the capacitance can be increased. Furthermore, miniaturization and high performance of electrolytic capacitors, and miniaturization and high performance of electronic equipment incorporating such electrolytic capacitors are possible.

Claims (19)

1. the manufacture method of an electrolytic capacitor usefulness aluminium is characterized in that, aluminium ingot is carried out hot rolling and cold rolling, implement process annealing thereafter, after the process annealing between the beginning final annealing, do not implement cold rolling and give tension strain, implement final annealing thereafter.

2. electrolytic capacitor according to claim 1 wherein, is given 1～15% tension strain with the manufacture method of aluminium.

3. electrolytic capacitor according to claim 2 wherein, is given 3～12% tension strain with the manufacture method of aluminium.

4. use the manufacture method of aluminium according to each described electrolytic capacitor of claim 1～3, it is characterized in that, have 2 units or be configured in bridle rolls unit on the aluminium conveyance direction more than 2 units, between adjacent bridle rolls unit, form the tension strain applicator of tension zone by use, the difference that circumferential speed Po in circumferential speed Pi in the upstream side bridle rolls unit and the downstream side bridle rolls unit is established Pi＜Po, make plastic elongation takes place in the mentioned strain zone continuously, carry out giving of tension strain.

5. the electrolytic capacitor according to claim 4 manufacture method of aluminium, wherein, above-mentioned circumferential speed Pi, Po satisfy the relation of 0＜(Po-Pi)/Pi≤0.1.

6. according to the manufacture method of claim 4 or 5 described electrolytic capacitors usefulness aluminiums, wherein,, produce above-mentioned difference by with the different revolution running upstream side bridle rolls units and the bridle rolls of downstream side bridle rolls unit.

7. use the manufacture method of aluminium according to each described electrolytic capacitor of claim 4～6, wherein bigger than the bridle rolls diameter of upstream side bridle rolls unit by the bridle rolls diameter that makes downstream side bridle rolls unit, produce above-mentioned difference.

8. use the manufacture method of aluminium according to each described electrolytic capacitor of claim 1～7, wherein, in giving 1 rolling pass of tension strain, give tension strain at 2 places or more than 2 places.

9. use the manufacture method of aluminium according to each described electrolytic capacitor of claim 1～8, wherein, repeatedly give the rolling pass of tension strain.

10. use the manufacture method of aluminium according to each described electrolytic capacitor of claim 4～9, wherein, above-mentioned tension strain applicator is the roller type tension flattening machine.

11., wherein, carry out process annealing and tension strain continuously and give according to the manufacture method of the described electrolytic capacitor of each of claim 1～10 with aluminium.

12., wherein, carry out continuously that tension strain is given and final annealing according to the manufacture method of the described electrolytic capacitor of each of claim 1～11 with aluminium.

13. according to the manufacture method of the described electrolytic capacitor of each of claim 1～12 with aluminium, wherein, making thickness is the aluminium of 110～230 μ m.

14. according to the manufacture method of the described electrolytic capacitor of each of claim 1～13 with aluminium, wherein, 0.2% yield strength of the rolling direction of the aluminium after the process annealing is 25～100Mpa.

15. according to the manufacture method of the described electrolytic capacitor of each of claim 1～14 with aluminium, wherein, in the diameter suitable with circle, there is not the coarse grain above the size of 2mm in the surface of the aluminium behind the final annealing.

16. according to the manufacture method of the described electrolytic capacitor of each of claim 1～15 with aluminium, wherein, above-mentioned aluminium is an anode material.

17. according to the manufacture method of the described electrolytic capacitor of each of claim 1～16 with aluminium, wherein, above-mentioned aluminium is the mesohigh anode material.

18. an electrolytic capacitor aluminium is characterized in that, is to make with each described method of claim 1～17.

19. an electrolytic condenser is characterized in that, uses the described electrolytic capacitor aluminium of claim 18 as electrode materials.

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